Telecommunication systems employ carriers that carry voice and data from one network element to another network element, such as a Digital Access and Cross-Connect System (DACS). DACS network elements are described generally in an article by R. P. Abbott and D. C. Koehler, "Digital Access and Cross-Connect System--System Architecture," NTC '81, IEEE, National Telecommunication Conference, vol. 1, pp. B.1.2.1-B.1.2.7 (1981). This article is incorporated by reference herein. The purpose of a DACS is to improve flexibility in routing channels by connecting the various carriers to one another via software. One such carrier is a T1.5 or T1 carrier. This carrier is a facility that carries a DS-1 or a level-one digital signal. More specifically, such a carrier carries twenty-four DS-0 channels each of which is a 4-kHz voice signal. One frame format samples the twenty-four DS-0 signals, converts them to a digital form and combines them into a frame. Twelve frames are then combined into a superframe. Finally, the twenty-four channels are multiplexed as one DS-1 signal on a T1.5 carrier. The T1.5 carrier, thus, terminates in a network element such as a DACS were the point of termination is a component known as a Network Processing Circuit (NPC).
Various systems are known in the art for DS-1 circuit and facility monitoring and performance. These systems include provisions for providing and detecting alarms when certain errors or malfunctions occur in a DS-1 circuit or facility. The alarms are then collected and analyzed. One such system is disclosed in U.S. Pat. No. 5,136,617, "Switching technique for attaining synchronization," which is incorporated by reference herein.
Currently, however, there exists no system for monitoring DS-0 circuit alarms, such as an alarm on an NPC in a DACS frame, in a format that is useful for a network management center (NMC). An NMC typically consists of personnel responsible for the surveillance and control of the flow of telecommunication network information in a specific geographical area or for a specific group of customers.